Gold base alloy



Patented Oct. 6, 1953 UNI TE D ,S TATES T OFF-WE GOLD BASE 141L150?! Victor G. Mooradian, EastiQrange,tN.;-:J., amixnnr to The H. A. Wilson Company,'-Newark,.N..-J., a corporation ,ofNcwJersey No Drawing. Application April 2, 1949,

. Serial No -85,261

reclaims. (ciao-.1219) This invention relates to gold-base-alloys, and more particularly to gold-base alloys containin silicon together with iron, chromium or zircornium for the jewelry trade.

1Go1d-basea1loys heretofore commonlyused for vi'making jewelry articles frequently develop the defect known :as orange peel when "the alloy .is alternately-subjected to annealing at a high temperature and severe mechanical working at *room temperature. This defect is characterized by a surface roughness similar in appearance'to the outer surface of the skin of an orange (though on a finer scale), whence comes the name orange peel. ,Itis objectionable because a great deal of polishing .is necessary to restorea smooth surface to the article on which it develops. It is particularly objectionable when it developson the gold alloy cladding layer of rolled old plate, because this thin layer is often polished completely through in the-eifort to obliter- -"g ate the orange peel roughness.

The gold alloys subject to development of orange peel roughness are mostly the, standard 1.0-,karat to 18-karat alloys containing about 1% to 55% copper, 1% to silver, 1-%'to 15% zinc, sometimes a fraction of 1% to 4% nickel, and the balance gold. (All percentages herein are by weight.) I have discovered that by the addition to such alloys of 0.01%to 1% silicon together with 0.1% to 3% of a metal selected from the group consisting of iron, chromium, and zirco-" -1.1;%- :nickcl always. ,1displays a umarkedprange peel surface condition whenassheetsoissuchmaterial subjected to :a treatment involving an- .neali-ns: .130 :the dead softscondition, then cold :rolling :to -;the :extent or 50% reduction in area, then annealingioralfi: imi-nuteszat .1800 -z-and thendrawingto theibreaking point awitlra zround bottom punch in a bottomless die. By incorporating 0.1% silicon and 1.0% iron, chromium or zirconium in this particular alloy (proportionately reducing theamounts of copper, silver :and zinc) ,the tendency .forit to develop orange peel is quite completely inhibited, both when it .is :given the same treatment just described and when given the even more severe treatment involving increasing the Qfinal annealing temperaturefrom 1300 F. to 1600.-F.

'The gold alloys of the invention are easily .fabricated into rolled gold plate by the customary procedure of bonding a layer of the new alloy to a bar .of-base metal and thenrolling the composite bar to the desired final thickness. The

provision of such compositemetal products is an especially advantageous feature of the invention, because the new gold-base alloy is able to vwithstand the high annealing temperatures to which the base :metal often .must be subjected, without developing orange peel roughness. The base metals used in the fabrication of rolled gold 0 ,plate (such, for example, as commercial L nickel, or composition metal--sometimes called igilding metal -which is basically a low-zinc nealsand working operations to which the alloy is subjected.

Especially satisfactory results have been obtained by the addition of from 0.05% to 0.5% silicon and from 0.5% to 1.5% iron, chromium or zirconium to a IO-karat to 14-karat yellow gold alloy of to 50% copper, 3% to 10% silver, 3% to 10% zinc, from none up to 2% of nickel, and the balance (usually about to 60%) gold. For example, a 10-karat alloy consisting of 41.6% gold, 42.0% copper, 7.1% silver, 8.2% zinc and brass, or a nickel silver :alloy composed of about 45% to copper, about 10% to 30% nickel, about 15% to 25% zinc, and sometimes a few per cent of tin and .lead) -:have annealing temperatures upwards-of 1000 F., and often must be heated to such temperature or higher in the course of being fabricated by cold working into intricate .jewelry articles. The standard karat gold alloys easily develop orange peel roughness when subjected to severe mechanical working after having been heated to thexbase metal annealing temperature above 1000 F., and particularly above 1200? F. Consequently, rolled gold plate made by bonding a standard karat gold alloy to a base metal having an annealing temperature above 1000 F. cannot be heated to the full annealing temperature of the base metal and then worked without developing orange peel roughness. Since the thickness of the gold layer on the finished plate is generally only a few thousandths of an inch, it is particularly undesirable to have orange peel develop on this very thin layer when it is fabricated into a watchcase or other jewelry item. Polishing the thin gold alloy layer at those points where orange peel roughness develops frequently results in wearing completely through the gold alloy layer. However, a composite metal product comprising a sheet of base metal having an annealing tem-- perature upwards of 1000 F. to which is bonded a surface layer or sheet of a gold-base alloy containing silicon together with iron, chromium or zirconium in accordance with the invention may be heated to the full annealing temperature of the base metal without having orange peel roughness develop to any significant extent at the surface of the gold alloy layer when the composite product is thereafter subjected to severe plastic deformation. 7

The inclusion of silicon together with iron, chromium, or zirconium has no detrimental effect on the corrosion resistance of the alloy, and may even improve it somewhat. Further, these alloys are precipitation hardenable by the process of heating to a temperature of about 1200 to 1300 F., quenching to room temperature, and then reheating at about 550 to 700 F. for about two hours. Advantage may be taken of this property in the fabrication of jewelry items in which rather high strength and hardness are desirable.

I claim:

1. A composite metal product comprising a sheet of base metal having an annealing temperature upwards of 1200 F. to which is bonded a surface layer a few thousandths of an inch in thickness of an alloy consisting essentially of 1% to 55% copper, 1% to 15% silver, 1% to 15% zinc, 0.01% to 1% silicon, 0.1% to 3% of a metal selected from the group consisting of iron, chromium, andzirconium, and the balance gold, whereby said composite metal may be alternately heated to above the annealing temperature of its base metal component and subjected to severe mechanical working at room temperature Without developing significant orange peel roughness at the surface of the gold alloy layer.

2. A composite metal product comprising a sheet of base metal having an annealing temperature upwards of 1200 F. to which is bonded a surface layer a few thousandths of an inch in thickness of an alloy consisting essentially of 1% to 55% copper, 1% to silver, 1% to 15% zinc, 0.01% to 1% silicon, 0.1% to 3% iron, and the balance gold, whereby said composite metal may be alternately heated to above the annealing temperature of its base metal component and subjected to severe mechanical working at room temperature without developing significant orange roughness at the surface of the gold alloy layer.

3. A composite metal product comprising a sheet of base metal having an annealing temperature upwards of 1200 F. to which is bonded a surface layer a few thousandths of an inch in thickness of an alloy consisting essentially of 1% to 55% copper, 1% to 15% silver, 1% to 15% zinc, 0.01% to 1% silicon, 0.1% to 3% chromium, and the balance gold, whereby said composite metal may be alternately heated to above the annealing temperature of its base metal component and subjected to severe mechanical working at room temperature Without developing significant orange peel roughness at the surface of the gold alloy layer.

4. A composite metal product comprising a sheet of base metal having an annealing temperature upwards of 1200" F. to which is bonded a surface layer a few thousandths of an inch in thickness of an alloy consisting essentially of 1% to 55% copper, 1% to 15% silver, 1% to 15% zinc, 0.01% to 1% silicon, 0.1% to 3% zirconium, and the balance gold, whereby said composite metal may be alternately heated to above the annealing temperature of its base metal component and subjected to severe mechanical WOlkll'lg at room temperature without developing significant orange peel roughness at the surface of the gold 7 alloy layer.

5. An alloy having increased resistance to the development of orange peel when ultimately subjected to annealing at high temperature and severe mechanical working at room temperature consisting essentially of from about 1% to 55% copper, from about 1% to 15 silver, from about 1% to 15% zinc, from about 0.01% to 1% silicon, from about 0.1% to 1.5% of a metal selected from the group consisting of iron, chromium and zirconium, and the balance gold.

6. An alloy as defined in claim 5 in which the metal of said group is iron.

7. An alloy as defined in claim 5 in which the metal of said group is chromium.

8. An alloy as defined in claim 5 in which the metal of said group is zirconium.

9. An alloy as defined in claim 5 in which the amount of copper is from about 25% to 50%.

10. An alloy as defined in claim 5 in which the amount of silver is from about 3% to 10%.

11. An alloy as defined in claim 5 in which the amount of zinc is from about 3% to 10%.

12. An alloy as defined in claim 5 which contains nickel in amount upto about 2%.

VICTOR G. I /IOGRADIAN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,571,540 Davignon Feb. 2, 1926 1,580,444 Shields Apr. 13, 1926 1,725,445 Davignon Aug. 20, 1929 1,712,244 Bek May '2, 1029 2,007,008 Staples July 2, 1535 2,141,157 Peterson Dec. 20, 1938 2,248,100 Loebich July s, 1941 2,229,463 Leach Jan. 21, 1941 2,270,594 Leuser Jan. 20, 1042 2,394,673 Edmonds Feb. 12, 1946 FOREIGN PATENTS Number Country Date 218,138 Switzerland Mar. 16, 1942 

1. A COMPOSITE METAL PRODUCT COMPRISING A SHEET OF BASE METAL HAVING AN ANNEALING TEMPERATURE UPWARDS OF 1200* F. TO WHICH IS BONDED A SURFACE LAYER A FEW THOUSANDTHS OF AN INCH IN THICKNESS OF AN ALLOY CONSISTING ESSENTIALLY OF 1% TO 55% COPPER, 1% TO 15% SILVER, 1% TO 15% ZINC, 0.01% TO 1% SILICON, 0.1% TO 3% OF A METAL SELECTED FROM THE GROUP CONSISTING OF IRON, CHROMIUM, AND ZIRCONIUM, AND THE BALANCE GOLD, WHEREBY SAID COMPOSITE METAL MAY BE ALTERNATELY HEATED TO ABOVE THE ANNEALING TEMPERATURE OF ITS BASE METAL COMPONENT AND SUBJECTED TO SEVERE MECHANICAL WORKING AT ROOM TEMPERATURE WITHOUT DEVELOPING SIGNIFICANT ORANGE PEEL ROUGHNESS AT THE SURFACE OF THE GOLD ALLOY LAYER. 